1. Field
This invention is in the field of cattle guard construction as commonly employed to extend cattle fencing protection across highways without obstructing traffic using the highways.
2. State of the Art
Cattle guards across highways are normally provided by constructing a double layer of steel rail grillwork on stepped, reinforced concrete piers that are cast in place at opposite sides of the highway, the upper surface of the grillwork being substantially flush with the highway surface. In northern climates subject to snowfall in the winter season, widely spaced steel strips are secured to the upper surface of the grillwork in longitudinal alignment with the highway as slideways for accommodating snowplows. Triangularly shaped end guards slope, from securement at their bases to the piers, upwardly and outwardly to approximately fence height at their vertices. The resulting cattle guard structure prevents cattle from crossing the unfenced highway portion of the normally fenced property line on pain of having their feet and lower legs caught in the grillwork. Long experience has shown that cattle will not normally cross such highway cattle guards and that ranch owners can be quite effectively protected from having their cattle stray, even though ungated highways cross their property.
Despite the effectiveness of such cattle guards, the expense of construction is considerable, and cattle and other livestock do at times attempt to cross and cannot be extricated without injury. Moreover, sometimes people attempting to walk across such cattle guards have their feet caught between the rails of the grillwork.
An attempt has been made heretofore to avoid certain disadvantages of the usual highway cattle guard, see Slaughter U.S. Pat. No. 2,471,551 of May 31, 1949, by a cast-in-place construction utilizing a deeply corrugated metal sheet closely topping a conformingly shaped concrete base. Yet, the aforedescribed customary construction remains in widespread use, probably because the Slaughter construction is impractical from a commercial standpoint.
3. Objectives of the Invention
Principal objectives in the making of the present invention were to reduce considerably the expense of fabrication and time required for installation of a highway cattle guard by providing a highly practical cattle guard construction, to provide for additions to an existing cattle guard if and when a highway is widened, to provide for easy and relatively inexpensive replacement of damaged portions of a highway cattle guard following initial installation, to eliminate or greatly reduce the danger of animals or people becoming inextricably caught in a highway cattle guard, and to provide a method of handling precast concrete slab sections so they may be easily placed in juxtaposition by customarily available lifting equipment and thereafter fastened together as a substantially rigid, unitary structure.